Yep, I didn't want to have to think about concurrency so my solution was a global lock file on my VM that gets checked by a pre-start hook in claude code. Each of my "agents" is a it's own linux user with their own CLAUDE.md, and there is a changelog file that gets injected into that each time they launch. They can update the changelog themselves, and one agent in particular runs more frequently to give updates to all of them. Most of it is just initiated by cron jobs. This doesn't scale infinitely, but if you stick to two-pizza teams per VM it will still be able to do a lot.

So hooks are your friends. I also use one as a pre flight status check so it doesn't waste time spinning forever when the API has issues.